This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The primary motivation of this project is to quantify the DNA quantity within a live cell without adding any extra agent. The refractive index of DNA has not been accurately measured near the ultraviolet range, but the reported absorption spectra suggest it has different dispersion characteristics from proteins. Hence, by measuring the refractive index map of a live cell at two or more different wavelengths, we expect to quantify three dimensional distribution of DNA within a live cell.